In general, tumors are found through touching or naked-eye observation, and the observation is usually assisted by instruments such as ultrasonic instruments or endoscopes. The endoscope primarily extends a soft tube with a camera and a light source device into a living body, and an external display device is provided for obtaining the information of the surfaces of organs and tissues in vivo. Further, a tissue section is sliced and collected in order to perform a pathological test. However, the endoscope just can provide the information of the surface of tissues only, but it is difficult to determine the existence of a tumor in subcutaneous tissues through the observation by the endoscope.
A change of tissue hardness is usually accompanied with a pathological change. For example, a subcutaneous tumor causes abnormal tissue hardness, and the test still requires ultrasonic endoscopes to obtain tumor information accurately. However, the ultrasonic endoscope is expensive and thus it is not popular among general medical institutions. Therefore, it is necessary to provide a simple and easy way of measuring the flexibility of tissues in a living body in order to examine whether there is a subcutaneous tumor and assist the diagnosis of diseases.
As disclosed in U.S. Pat. No. 8,328,730 entitled “Living body measurement apparatus”, the living body measurement apparatus includes a contact section which includes a first contact surface contacting a living body and which applies pressure to the living body, an auxiliary section disposed on an external side of the contact section and including a second contact surface contacting the living body, and supporting the second contact surface, so that the second contact surface performs reciprocating movement between coplanar positions and drives the second contact surface to retract to the position of the first contact surface, and the first contact surface and the second contact surface are disposed on the same plane, and a first pressure sensor is installed for measuring pressure applied to both of the contact section and the auxiliary section. The measurement apparatus includes a support section for supporting the auxiliary section, a first elongated groove formed between the auxiliary section and the support section and extended in a reciprocating direction of the reciprocating movement of the second contact surface, a second elongated groove which is formed in the one of the auxiliary section and the support section and which extends in a direction perpendicular to the reciprocating direction, a protruding portion which is formed in the other of the auxiliary section and the support section and which is disposed at either one of the first elongated groove, so that the locking mechanism is configured to lock the auxiliary section in a state in which the second contact surface is disposed at the retracted position, such that the hardness of muscular tissues and the pain of a patient can be measured by a single instrument.
As disclosed in U.S. Pat. No. 4,159,640 entitled “Apparatus for measuring the consistency or hardness of a material”, the apparatus includes a cylindrical housing enclosing a spring with the degree of pre-straining of which, in compression, is adjustable by means of screw, and the spring pushes a piston towards the material, and the end of the piston fixedly carries a feeler, and the displacement of the piston in the cylindrical housing is registered by means of a conventional type of displacement sensor which delivers a continuous voltage output proportional to the displacement of the feller from a reference position, and the housing includes stops for limiting the travel of the piston, thereby defining the aforementioned reference position. Therefore, this apparatus can be used for testing a material having variable pressures and measuring the hardness of elastic material (such as skin) accurately.
As disclosed in U.S. Pat. No. 5,766,137 entitled “Frequency deviation detecting circuit and measuring apparatus using the frequency deviation detecting circuit”, the apparatus includes an oscillator for generating a mechanical oscillation, and a detecting element for detecting the oscillation information, and a feedback circuit for feeding back a feedback signal of the oscillator based on the oscillation information, and driving the oscillator into a first resonant state, and the oscillator has a central frequency of the first oscillator, a gain variation compensating circuit installed to the feedback circuit, and the central frequency of the gain is different from the frequency of the oscillator applicable for increasing the gain in response to a change of frequency. If the frequency changes, the oscillator shifts from the first resonant state to a second resonant state, and the oscillator has a second oscillation central frequency, and the apparatus detects the deviation between the central frequencies of the first and second oscillators, and this apparatus is applied to the apparatus for measuring hardness and detecting the hardness of biological tissue (such as skin or internal organ).
In addition, the inventor of the present invention also filed a sensor related patent as disclosed in U.S. patent application Ser. No. 13/116,092 entitled “Apparatus and method for identifying a tissue in a living body”, and the apparatus comprises a sensing element for sensing tissue parameters, a manipulating device for manipulating the sensing element, and an analyzing element for analyzing the meaning of the parameters. The sensing element is placed near an object to be tested and forces are applied to both of the top and bottom ends of the sensing element, so that a contact force is produced between soft tissues and the sensing element to cause deformation, and the deformation is measured and its corresponsive voltage value is read, so that a ratio of voltage values or a reflected stress ratio may be used to estimate the tissue to be tested and the material property related to hardness.
However, the aforementioned patent primarily aims at the aspect of sensors, and the control of forces is essential to the sensors, so that the sensors still require an appropriate firing device for triggering the sensor and touching the object to be tested in order to obtain measured values and continue the measurement.